How can I access the web interface of a Peplink router?

The easiest way is via https://incontrol.ascend.de
In rare cases, however, the router is displayed as offline although it should actually be online.
In these cases, the following can be checked/tried:

• Check whether the connection to the Fusionhub still exists.
  • If necessary, set up a port forward here and use it to access the router’s web interface
  • Connect to the Fusionhub via VPN and from there to the router’s web interface
• If the router has a public WAN IP, access can be attempted via this
• Access to the LAN IP via a connected PC